No 4K output (i7 8700, asrock itx z370 fatality)

[achan180]

I have an i7 8700 running on an asrock itx z370 fatality. The computer's onboard graphics do not output 4k on the hdmi port (or video at all on my 4k monitor). Video is displayed when I use a hdmi to dp converter (and switch to the computer's dp), but this is limited to 1080p. Using a 4k cable.

I can use wireless monitor to get 4k at 30hz, so the pc is obviously 4k capable.

Would appreciate any advice.

[n_scott_pearson]

Your processor can simultaneously support three display outputs. Two output formats are supported:

1. When configured to output in HDMI 1.4 format, each output is capable of supporting a full 4K (4096x2304) monitor at 24Hz and a standard 4K (3840x2160) monitor at 30Hz.
2. When configured to output in DisplayPort 1.2 format, on the other hand, each output is capable of supporting a full or standard 4K monitor at 60hz.

The DisplayPort 1.2 format output can be exposed in any of three ways:

1. Directly via a DisplayPort or mini DisplayPort connector.
2. Passed through a USB-C connector, either as part of a Thunderbolt 3 signal or as part of a USB-C signal that is also supporting DisplayPort Alt Mode.
3. Passed through a LSPCon IC on the motherboard, which will convert the signal to HDMI 2.0 format and support a full 4K monitor at 60Hz.

According to your board's web page, all three outputs are configured for DisplayPort 1.2 format and these are exposed via Displayport, USB-C (with Thunderbolt 3) and HDMI 2.0 connectors, which means all three of the output methods listed above are supported.

Now, you say that, via the HDMI connector, you cannot get a display. This can be caused by a fault in the LSPCon IC, down-rev. firmware in the LSPCon IC or a bad or poor quality HDMI cable. After verifying that you are running on the latest firmware available for the LSPCon IC, seeing the output not working will typically mean you have a bad or poor quality HDMI cable. Even if this cable seems to work on another PC, get a replacement to use with this PC. Remember, you get what you pay for. My rules for cables that come with monitors is: (a) they are universally crap, (b) they should never be relied upon to support 4K connections and (c) your best bet is to immediately throw them in the garbage.

If you are looking at using the USB-C connector, be very careful in the selection of any USB-C-to-HDMI adapter or cable that you purchase. Unless it specifically says that it supports 4K@60Hz and HDR, it likely doesn't.

Hope this helps,

...S

[achan180]

thanks that is very detailed. could you tell me how to upgrade the firmware on the  LSPCon IC? I have run intel driver and support and everything seems to be up to date. LSPC was never mentioned in any of this.

I have tried using 3 different 4k cables and they all seem to not work, unless i plug a display port adaptor on either of them and then it outputs at 1080p. My 4k hdmi to dp cable as well does not output any image. Seems like too much of a coincidence for all three not to work.

Could you tell me how to verify that I am running on the latest firmware available for the LSPCon?

Thanks again Scott

[n_scott_pearson]

I have no idea which IC they chose to use or how it is updated. I would start by looking to see whether they have any updates on their web site.

You said HDMI-to-DP. Did you not mean DP-to-HDMI? Once you have gone through the DP to HDMI protocol conversion, you cannot then go back to DP. This is why (if this is indeed what you attempted) you did not see any image.

What are you using for monitor(s) and what inputs do they offer?

...S

[achan180]

Using a samsung q60 tv. It only has hdmi as input ports, I have tried multiple so it is unlikely to be a faulty port. I have a hdmi cable that I used a dp converter on and this gives me 1080p. i have a 4k cable that has hdmi on one end and dpi on the other, which gives me no image.

I'll message asrock and see what they say, all the drivers seem to be up to date. Maybe they have some sort of fix.

I really do appreciate all the time you have spent walking me through all of this